noctilucent cloud
Sign in to savehighly-elevated cloud-like ice crystals in the upper atmosphere of Earth visible during astronomical twilight
AI overview
Noctilucent clouds are thin, icy clouds that form very high in Earth's atmosphere and can be seen glowing during twilight hours when the sun is below the horizon. Scientists study them because their presence and behavior may provide clues about atmospheric conditions and changes in Earth's upper atmosphere.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Abbreviation
- NLC/PMC
- Altitude
- 76,000 to 85,000 m, (250,000 to 280,000 ft)
- Classification
- Other
- Precipitation
- No
via Wikipedia infobox
Article
Noctilucent clouds (NLCs), or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere. When viewed from space, they are called polar mesospheric clouds (PMCs), detectable as a diffuse scattering layer of water ice crystals near the summer polar mesopause. They consist of ice crystals and from the ground are only visible during astronomical twilight. Noctilucent roughly means "night shining" in Latin. They are most often observed during the summer months from latitudes between ±50° and ±70°. Too faint to be seen in daylight, they are visible only when the observer and the lower layers of the atmosphere are in Earth's shadow while these very high clouds are still in sunlight. Recent studies suggest that increased atmospheric methane emissions produce additional water vapour through chemical reactions once the methane molecules reach the mesosphere – creating, or reinforcing existing, noctilucent clouds.
General